Tuning control for radio receivers or the like



Nov. 14, 1939. w KE N r AL 2.179.576

TUNING CONTROL FOR RA'DIO RECEIVERS OR THE LIKE Filed May 24, 1937 4 Sheets-Sheet 1 N 14, 1939. M, w ENNEY H A, 2.179.576-

TUNING CONTROL FOR RADIO RECEIVERS OR THE LIKE Filed May 24, 1957 4 Sheets-Sheet 2 Nov.14,1939. M.W.KENNYILIYETAL 2.179.576

TUNING CONTROL FOR RADIO RECEIVERS OR THE LIKE wfz enrfy N Mew a. Gedde Nov. 14, 1939. M. w- KENNEY ET AL 2.179 576.

TUNING CONTROL FOR RADIO RECEIVERS OR THE LIKE Filed May 24, 1937 4 Sheets-Sheet 4 Qndrew a. Ga'de @y;-@,1 7720022,

Patented Nov. 14, 1939 UNITED STATES TUNING CONTROL FOR RADIO RECEIVERS OR THE LIKE Mahlon W. Kenncy, Oak Park, and Andrew A.

Gedde, Chicago, Ill. 7

Application May 24, 1937, Serial No. 144,387

6 Claims.

This invention relates to a device for tuning a radio receiver or the like.

In so-called automatic tuning devices for tuning a radio according to the call letters of a desired broadcast station, the individual controls must be initially preset or adjusted in their relations to the tuning element so that each control will thereafter move the tuning element to the proper position required to tune the receiver to a particular selected station. This presetting or adjusting operation is complex in character because of the complexity of the mechanism and requires for its performance partial disassembly of the control mechanism. Accordingly, the practice has arisen of having a factory or sales representative make the original adjustment after ascertaining from the prospective user the stations which he customarily selects. If later the tuning position for one or more of these selected stations varies, as it almost universally does, or if it is desired to change from one automatically selectable station to another, the mechanism must be disassembled, adjusted and reassembled. This requires for satisfactory performance the services of a radio technician or service man and results in consider- 25 able expense.

Furthermore, in such present automatic devices the adjustment permitted is only rough in character, reliance being had to a large extent upon the functioning of the automatic frequency control to bring the receiver frequency in step with the carrier frequency. The adjustment of the control to select stations whose carrier frequency is close to that of a local, high power station is therefore made impossible. It is accordingly an object of applicants invention to provide an automatic tuning control which shall include simple and readily manipulatable presetting means for adjusting the control properly to select the desired stations.

Another object is to make such adjustable means accessible and operable without disassembly of any part or portion of the automatic control, and specifically to provide means permitting presetting of the automatic control from the front of the operating mechanism.

A further object is to provide efficient and sensitive means for precisely adjusting or presetting automatic tuning controls for radio receivers or the like.

A further, more specific object of the invention is to provide in a selective adjusting mechanism of the type disclosed in applicants copending application, Serial No. 100,156, filed September 10, ,0 1936, improved means for presetting and adjusting the mechanism properly to select the desired stations.

A further object is to provide an automatic tuning device of a simple, compact and efficient construction capable of ready adjustment to effect (iii a change in the stations automatically selectable by operation of the device.

Other objects and advantages of the present invention will more fully appear from the following detailed description, which, taken in connection with the accompanying drawings, will disclose to those skilled in the art the construction and operation of a preferred form of the present invention.

Fig. 1 is a front view of a tuning device embodying the invention.

Fig. 2 is a vertical section taken on the line 2-2 of Fig. 1.

Fig. 3 is a vertical section taken along the line 3-3 of Fig. 2.

Fig. 4 is a fragmentary vertical section taken along the line 4-4 of Fig. 2.

Fig. 5 is an enlarged fragmentary vertical section taken along the line 55 of Fig. 2.

Fig. 6 is a vertical section taken along the line 6-6 of Fig. 2.

Fig. '7 is an horizontal section taken along the line 1-1 of Fig. 6.

Fig. 8 is a fragmentary view of exploded perspective of certain parts of the mechanism.

Fig. 9 is a fragmentary enlarged vertical section similar to Fig. 2 and showing a difierent position of operation of said mechanism.

Fig. 10 is an horizontal section taken along the line Ill-l0 of Fig. 9.

Fig. 11 isa view similar to Fig. 10 with the parts in a different position of operation.

Fig. 12 is a schematic illustration of the control circuit embodied in the invention.

As shown in the drawings, applicants invention embodies a supporting frame or casting 2 (Fig. 8), substantially in the form of a disk having an annular guide portion 4 and a recessed body portion 6. The body portion 6 is provided centrally with a rearwardly extending, circular housing or boss 8 and a radially extending offset portion In communicating with the portion 8 and forming therewith a housing for elements later to be described.

The casting 2 is provided with reinforcing webs l2 (Figs. 2 and 6) extending radially from the portion -8 and adjacent thereto these webs are provided with bosses I4, the bosses l4 being threaded to receive screws It for attaching to the casting 2 a rear cover plate or housing I8. A slot is cut in the lower edge of the casting 2 in radial alinement with the center of the housing formed by the portions 8 and Ill, and'this slot communicates with a slot 22 formed in the guide portion t of the casting 2. As will be seen in Fig. 8, the slot provides a pair of lips 24 of less height than and partially closing the slot 20.

The lower part of the rear wall of the offset portion ID is cut away to expose a set of four contacts 26, 28, and 32 (Figs. 2, 6 and 8 to 12) which are mounted upon an insulating block 34 secured to the rear Wall of the portion II] in any convenient manner. Within the rearwardly extending boss or portion 8, .there is mounted a stationary axle or bushing 36 (Figs. 2, 4 and 6) which passes through an aperture in the rear Wall and is secured in any convenient manner Q39.

The bushing 36 is provided with an" enlarged opening 30 extending inwardly fr'oinf one' said wall.

end to receive a lamp socket 42 and a lamp M; a lamp cable 45 passing throughacentral opening 48 in the bushing 35.

A control wheel or gear 50 (Figs. 2 to 5, 8 and 9) is rotatably mounted by its hub portion 52 on the bushing 36 to which it is secured against longitudinal movement by the rear wall of the portion 8 of the casting 2 and by a collar 54 secured to the outer end of the bushing 36 by a'set' screw 55.' The collar 54 is provided with forwardly extending radial arms 58 upon which is mounted a ring 60 to which is secured a transparent or translucent disk 62 carrying the usual indicia'representative of radio broadcast frequen cies.

A cover member 64 (Fig. 2) is secured to the wheel 50 for rotationtherewith by a plurality of screws 56 threaded into the outerends of pedestals 68 (Figs/2 'and 3) formed integrally with and projecting forwardly from the wheel 55. The cover member 5 1 is provided with a central opening IE3 for receiving the customary glass or crystal 12, through which the dial plate 62 is visible. The cover member'fi t is further provided with a plurality of ann'ularly arranged; fingerreceiving openings I4 (Figs; 1, 2 and 9) and an index or pointer Iii cooperating with the dial plate 62. A front cover member "I8 is spring pressed over the rear cover member I8 at their meeting edges and is provided with an inturned, annular flange (Fig. 2) cooperating with an outwardly extending annular flange 82 and the periphery of the-cover member 54 to seal the enclosed mechanism. The cover member M is provided with a rearwardly extending annular flange 84 slotted at equally spaced points in alinement with the centers of the openings 14 to form guideways 85 for a purpose later to be described. 7 The wheel 58 is provided on its rear surface with an annular series of integrally formed ratchets 88 (Figs. 2,4, 5 and 8 to 11). An opening Sill extends through" each of the ratchets and the bodyof the wheel 50 for the purpose'of slidab ly receiving the pin 92 of a dog 94 which carries a pawl 96 provided with teeth 98 for cooperation with the teeth I00 of its associated ratchet 88. The teeth I00 of each ratchet 83 are'formed' concentrically to the opening and, like the teeth 98fare in the form of'isosceles triangles to prevent rotational movement but to permit longitudinal movement of the dog relative'to the ratchet. 'Each dog '94 is apertured as at I62 'to receive the shank m4 of a push button I06 (Figs. 2, 8, Qand 12) which is secured thereto by a slotted spring clip or collar I08 frictionally engaging in a groove formed o'n'the outer end of the shank IIM and engaging the outer surface. of the pin 92. Axial movement of the dog 94 relative to the push button IDS is prevented by the collar I08. and by the engagement of themner end of the pin 92 with a collar H5 formed by an enlarged portion N2 of the push button Hi6. Each push button 06 carries a cup-like member iI i having a lip H5 of slightly greater diameter to form a shoulder H8 for supporting a translucent or transparent marking disk I25, upon which is inscribed the call letters of a particular broadcast station. The push buttons I05 are in number equal to the number of fingerreceiving openings M and the ratchets (it; in the drawings fourteen such push buttons,.,openings and ratchets have been shown, although it will besapparent that any number may be provided depending upon the size of the device.

with and slidably received in a slot 86 formed in the flange 84 of the cover member 55.

Eaohpush button is normally urged to its forward position by a spring 524 which surrounds a boss IZt through which the opening 90 extends and the forward movement'of the push button is limited by an annular flange I28 formed on the cup-like member H4 adjacent the lip IIS. Theupper or inner halves of the cup-like members "Hi l are cutaway to permit rays of light from'the lamp'tfi to pass into the cup member and be reflected by the inner reflecting surface of the cup member to illuminate the marking disk I28.

A toothed'contact disk I38 (FigsQZ, 4, 8, 9 and 12) is mounted on an insulating disk I32 secured by studs H54 and springs I36 to bosses I38 formed in the 'wreel 5i] and extending rearwardly there-- from. The teeth of the contact disk I30 are alined with the push buttons Ilit so that,-upon rearward movement of the push buttons the shank IM will contact the teeth of the disk and complete a circuit through the push button and the wheel 5? to the grounded frame'Z. The studs E34 and springs E35 permitmovement of the contact strip I39 and insulating disk ltz'rearwardly relative to'thewheelfit, as seen in Fig. 9, the springs I35 normally holding the disk I32 in its forward po sition in engagement with the bosses I 38 (Fig. 2) Ribs Mil (Figs. 2 and 3) extending radially from the hoses Hi8,- provide' reinforcement for the Wheel 50. A sprin contact strip or blade I42 (Figs. 2, 6'a'nd l2) is secured to the recessed portion 6 of the frame casting 2 by the usual insulat ing strips and by insulated contact bolts I44 which pass through the portion '6 and carry on their buter ends any usual means for receiving and securing an electric conductor thereto.

Each dog 9 is provided with a rearwardly extending 'pin I l-5 (Figs. 2, 5 and 8 to 12) which, upon movement of the push button I06, engages an upstanding lug M8 carried by a pivoted stop member I513. The stop member I50 is pivoted by a pin I 52 to a bracket 54 carried between a pair of'brackets 556 and I58 formed integrally with and depending from the frame 2. The upstanding lug I 38 of the stop member I50 is provided with a right-angle, rearwardly extending leg Hill which overlies the lips 24 and is centered with respect to the slot 22; the leg I60 being adapted to engage the edges of the slot 20 to limit' the rotation of the stop member I50. An arcuate cam i 62 is formed integrally with the stop member I59 and extends rearwardly therefrom, the rear surface IM being in the form of a shallow V, and operatively engaging a cam roller I66 pivoted in-a bracket IE8 carried by the contact 30. The pin I46, carried by the dog 94, is adapted under certain circumstances to pass through the slot 22 between the lips 24' and operatively engage an U-shaped bracket I'It afiixed tothe lower end of the contact member 28;

The brackets I56 and I58 carry bosses I12 and I'M which form bushings for shafts I16 and H8. The shafts H6 and H8 extend through the front cover member it and carry on their outer ends manually operable knobs Hit and I82, respectively, the shaft I!!! having secured thereto intermediately the boss I'M and the cover '58, a gear for meshing engagement with the gear teeth on the wheel 50. Flexible cables Hi5 and I88 are coupled to the shafts H5 and H8, cable I86 being connected to the volume control (not shown) and the cable m8 being connected to the tuning element or condenser 253 of a remotely located radio receiver (not shown), the coupling between the shafts I'iii and H8 and the tuning and volume control shafts of the radio receiver being any of the usual well known forms.

The rear cover member or plate it may be additionally secured to the frame or casting 2 by screws I921 threaded in the radially extending openings H92 as shown in Fig. 5, and the entire mechanism may be supported upon the steering column or tube of an automobile by a pair of adjustable brackets 594 bolted to the rear cover member is. The cover member I8 and the frame 2 may be grounded by the bracket I9 1 or a separate grounding conductor may be provided, as desired.

In Fig. 12 there is schematically shown the circuit for the contacts 25 to 32 and for the contact disk I36. A number of push buttons Hi8,

which cooperate with the contacts 28 to 32 and the contact disk E33 to complete certain. circuits, are schematically represented in Fig. 12 as being grounded, this ground connection being efiected through the wheel 5t and the grounded frame or casting 2. The switch contact 26.is connected by a wire was to the conventional silencing circuit by which the speaker, or some other portion of the radio receiver, is rendered inoperative to transmit signals whenever the supply lead is grounded during the operation of the automatic tuning control. The switch contact 28 is connected by a wire I98 to the spring contact strip or blade M2 which is in engagement with the contact disk 9353. The switch contact Jill is provided with no external connection but is adapted to be connected by the stop member d and one of the dogs 84 to a grounded push button we. The switch contact 32 is connected by a wire 2M to the automatic frequency control circuit of the radio re ceiver, this automatic frequency control circuit being conventionally rendered inoperative by grounding the normally ungrounded supply lea-. It is this normally ungrounded supply lead which is connected to the wire 2%.

The bracket Hi l, upon which the stop member HE! is pivoted, carries at its outer end a Y-shaped bracket or plate M12, uponwhich is supported a pair of conventional control switches 2M and 2%, the operating of which extend through the front cover member I8 and are employed in the conventional manner to energize and control the radio receiver.

The operation of the above described mecha nism is as follows: The operator inserts a finger through one of the finger-receiving openings Hi and pushes the associated push button I06 rearwardly into engagement with the contact disk ltd to ground the lead 1% and silence the receiver during the tuning operation, the rear ward movement of the push button being limited by the engagement of the pin Mil with the surface of the guide portion i of the frame 2.

The operator then rotates the cover member M and attached wheel 50 in either a clockwise or counterclockwise direction as he may desire. When the operated push button has been moved to its lowermost position, the pin I46 will engage the lug N3 of the stop member I50, the cam I62 of which moves the cam roller I66 rearwardly to cause the contact 30 to engage the contact 32, thus grounding the lead 260 from the automatic frequency control circuit. This grounding of the automatic frequency control circuit renders it inoperative and prevents powerful local stations from interfering with the tuning of the receiver to the desired station. The stop member I50, in being rotated in a clockwise or counterclockwise direction, as the case may be, moves a distance sufficient to permit the pin I46 to aline itself with the slot 22 between the lips M of the casting 2, and this movement of the member I50 is limited by engagement of the leg I with a side of the slot ZEI to a distance equal to one-half the sum of the widths of the slot 22 and the leg I60. This controlled movement of the stop member 50 in either direction assures the identical positioning of the wheel 50 regardless of the direction in which the cover member 64 is rotated. The rotation of the gear 50 is transmitted by the gear I84 to the tuning shaft H8 and by the tuning cable M8 to the tuning element I89.

In order to preset a push button to a particular station, or to change an adjustment previously made, the control knob I82 is operated to rotate, through the gear I34, the Wheel 58 and cover member 64 to the approximate tuning position for the desired station, according to the wave length indicated on the dial plate 52. The push button I06, which is nearest the lowermost position, is then pushed rearwardly and the cover member 54 rotated until stopped by the engagement of the leg Hill of the stop member I59 with the side of the slot 26, the stop member I50 being rotated by engagement of the pin I 46 with the lug I 48 until the pin IE6 is alined with the slot 22. The push button I06 is then pushed rearwardly farther, the pin I 46 moving into the slot 22 where it engages and moves rearwardly the contact member 28 to break the connection between the leads I96 and I98 and thereby render the silencing circuit inoperative.

The movement of the dog 94 which causes the pin M6 to move into the slot 22 also causes the teeth 98 of the pawl 96- to disengage the teeth ll'm of the ratchet 88 and the wheel 50 is now free to rotate relative to the dog 94, this rotational movement being limited by pins 208 which extend rearwardly from between the adjacent pairs of ratchets 88. When the silencing circuit has been rendered inoperative, by breaking the connection between the contacts 26 and 28, the manually operable knob I82 is rotated slightly in the proper direction sharply to tune the receiver to the particular, desired station. The tuning having been accomplished, the push button M36 is released and is returned by the spring I 24 into its original position, the dog 9G assuming a new fixed position relative to the ratchet 88.

Asmall marking disk I20, carrying the call letters of the station to which the receiver has thus been tuned, is now inserted into the button Hi5 and is illuminated by rays of light from the lamp s4. Thereafter, whenever this particular push button M36 is depressed and rotated with the cover member M until stopped by the stop I applicant has provided a simple, eflicient and readily operable means for presetting and adjusting an automatic tuning control mechanism without disassembly of any part or portionof the automatic control, and specifically has provided means operable by the selectively operable push buttons of the automatic control mechanism for presetting and adjusting said mechanism from the front thereof.

It is thought that the invention and numerous of its attendant advantages will be understood from the'foregoing description and it is obvious that numerous changes may be made in the form, construction and arrangement of the several parts without departing from the spirit or scope of the invention, or sacrificing any of its attendant advantages, the form herein described being a preferred embodiment for the purpose of illustrating the invention, and the right is hereby reserved to make all such changes as fairlyfall within the scope of the following claims.

tuning element, selector means for shifting said first means to predetermined positions whereby to tune the receiver to selected broadcast stations,means operable'by said selector means for silencing the receiver during operation of said selector means and said shiftable means, releasable means connecting said selector means to said shiftable means for permitting relative adjustment of said shiftable means and said selector means thereby to vary the positions to which said shiftable means and said tuning element are movable by said selector means and means operable by said releasable means for rendering said receiver operative during relative adjustment of said-selector means and said shiftable means.

2. In a tuning mechanism for radio receivers or the like comprising a tuning element and an automatic frequency control circuit, the combination of shiftable means for operating said tuning element, selector means for shifting said first means to predetermined selected. positions whereby to tune the receiver to predetermined broad cast stations, releasable means connecting said last means to said shiftable means and operable by said selector means for permitting relative adjustment of said shiftable means and said selector means thereby to vary the positions to which said shiftable means and said tuning element are movable. by said selector means, and means operable by said releasable means for rendering said automatic frequency control circuit inoperative during relative adjustment of said selector means and said shiftable means.

3. Selective adjusting mechanism for radio receivers and the like comprising a manually shiftable element, and selective means operable during and as a part of the shifting of said element 3 said last element is moved by said selectors, said manually shiftable element comprising a wheel rotatable on an axle, means forming a stationary indicator dial, index means carried by said wheel in position to cooperate with said dial for indicating the adjusted positoin of said Wheel, means for supporting a lamp on said axle in position behind said indicating dial to illuminate the same, said selectors comprising depressible buttons, and indicia means on said buttons for indicating the adjusted position of the mechanism controlled by the selectors, said buttons being formed and supported in position to be illuminated by said axle supported lamp.

4. In a tuning mechanism for radio receivers or the like comprising a tuning element, the combination of shiftable means for operating said tuning element, means for silencing the receiver during operation of said tuning element, a plurality of selector means for shifting said shiftable means, a fixed stop member, means associated with each of said plurality of selector means and cooperating with said stop member for stopping said shiftable means in different positions, looking means operable to a released position by each' of said plurality of selector means for permitting adjustment of said stopping means relative to said shiftable means by manual operation of said shiftable means thereby to predetermine the positions to which said shiftable means is movable by said selector means, and means responsive to the release of said locking means to render said receiver operative during relative adjustment of said stopping means and said shiftabie means.

5. In a tuning mechanism for radio receivers and the like comprising a tuning element, a tuning shaft for operating said tuning element, a plurality of selector means for controlling operation of said tuning shaft to stop said tuning element in predetermined selected positions, said selector means being individually adjustable relative to said tuning shaft to predetermine the selected positions in accordance with the desired broadcasting stations, means for maintaining each of the plurality of selector means in adjusted position, means for silencing the receiver during each tuning operation, means for releasing said maintaining means to permit adjustment of its associated selector relative to the tuning shaft, and means responsive to the operation of said releasing means for rendering said receiver operative during relative adjustment of said selector means and said tuning shaft.

6. In a tuning mechanism for radio receivers and the like comprising a tuning element, the

combination of shiftable means for operating said tuning element, selector means for shifting said first means to predetermined positions whereby to tune the receiver to selected broadcasting stations, at silencing circuit selectively controlled by said selector means for silencing the receiver during operation of said selector means and said shiftable means, releasable means connecting said selector means to said shiftable means for permitting relative adjustment of said shiftable means and said selector means thereby to vary the positions to which said shiftable means and said tuning element are movable by said selector means, and switch means operable by said releasable means for breaking said silencing circuit to render said receiver operative during relative adjustment of said selector means and said shiftable means.

MAHLON W. KENNEY.

ANDREW A. GEDDE. 

